It is known that barcodes were first invented in 1932 through a thesis entitled “automation of calculation in supermarket” by Wallace Flin, and are currently printed on almost all items. A point of sale (POS) system automatically manages a buying process or a selling process using the barcodes. Further, the use of the barcodes has been rapidly increased with development of information technology (IT) for mail automation, factory automation, inventory control, library management, documentation management, and medical information management.
The barcodes are classified into two categories, that is, 1-dimensional barcodes such as Universal Product Code (UPC), European Article Numbering (EAN), Korean Article Numbering (KAN), code39, code93, and code128, and 2-dimensional barcodes such as code49, code16K, PDF-417, codablock, datacode, vericode, softstrip, and code1. The 2-dimensional barcode can contain up to 5,000 letters.
Readers for recognizing the barcodes include a laser reader, a light emitting diode (LED) reader, and a charge coupled device (CCD) reader according to devices used for the readers. Among them, the laser reader has been widely used because it can rapidly recognize the barcode. However, the laser reader is problematic in that it may recognize only the 1-dimensional barcode and is relatively expensive.
In recent years, there have been developed many readers using the CCD that can recognize the 2-dimensional barcode containing much information.
Meanwhile, with the advent of a smart phone, an application for acquiring a barcode image in real time and searching for a price and a bottom price of goods is developed.
A barcode signal is configured by continuously combining black and white modules, and information is encoded depending on a width of each module and a ratio of the modules. In order to precisely decode information, a size of each module must be restored within a margin of error. However, a barcode image acquired by a photographing means such as a camera may be blurred by focusing of the camera, and image noise may be caused by non-uniform illumination and barcode exposure environment at the time of acquiring the image. Thus, these factors must be overcome.